Since 1999, there has been a new anticorrosive pigment on the market, combining the hiding power of a white pigment with anticorrosive properties. This pigment is based on a titanium dioxide carrier material, which provides physical properties like light scattering [5.94, 5.95]. The surface of this titanium dioxide is treated with phosphate-containing anticorrosive substances (manganese aluminum phosphates) by a precipitation process comparable to the procedure used in order to reduce the photoactivity of titanium dioxide pigments. In addition this pigment is organically treated to provide good dispersing properties in both polar inorganic and organic media, which might be of importance for use in water — and solvent borne protective coatings [5.94, 5.95].
This pigment is said to be bifunctional. It combines corrosion protection and light scattering in a single pigment [5.95]. It is recommended for application in water — and solvent-borne primers as well as in cathodic electrodeposition coatings and coil coatings [5.95]. The typical properties of this anticorrosive are summarized in Table 5.12.
Tab. 5.12: Typical properties of treated titanium dioxide pigment [5.96].
|
5.2.11